1. Technical Field
This invention generally relates to milking liners.
2. Background Information
Automatic milking machines have been used to extract milk from different mammals through most of the past century. Most of these machines include a claw that typically has four nipples that are connected to teat cup assemblies that are attached to the teats. The teat cup assemblies include a rigid (hard plastic or metal) shell with a resilient milking liner (also known as a milking inflation) disposed within the shell. A short milk tube extends from the liner. A vacuum source is applied to the short milk tube and an alternating vacuum is applied to the shell to cause the liner inside the shell to collapse and expand and thereby massage and suck milk from the teats. The milk flows from the liners, into the short milk tube, to the nipples of the claw, and from there through a conduit to a collection tank.
The liner is one of the few components of an automatic milking machine that comes into direct contact with the animal. Liners have to collapse and expand to massage the teat to cause milk to flow. Numerous milking inflation designs have been developed for collapsing on the teat in different manners. The art desires an inflation having an open, relatively large, readily collapsible sleeve that uniformly collapses around the teat to provide effective and comfortable milking. The structure of the sleeve should provide a reliable collapsing configuration and a long useful life. Liners that collapse and expand slowly are undesirable. Liners that pinch or otherwise irritate the teat are also undesirable.
Another problem with existing liners is the tendency for the short milk tube to tear when the liner is removed from the teat and left to hang from the claw nipple by the short milk tube. When left to hang from the claw, the short milk tube is bent against the tip of the claw nipple causing the claw nipple to press into the inner surface of the short milk tube. In this position, the claw nipple can damage and eventually tear into the inner surface of the short milk tube. The damage and tearing is hastened when the hanging liners are jostled or unintentionally pulled from the milk claw in a direction that peels the short milk tube from the connector tube. The art desires a short milk tube design that resists damage and tearing